五氟磺草胺防除水直播稻田杂草效果

2.5%五氟磺草胺油悬浮剂(稻杰)是美国陶氏益农公司生产的新型稻田除草剂,为了验证其对直播稻田杂草的防除效果,2004年我们进行了田间试验,现将试验结果报告如下。1材料与方法1.1供试药剂2.5%五氟磺草胺油悬浮剂(稻杰,美国陶氏益农公司生产);36%苄·二氯(秧草净可湿性粉剂,江苏常隆化工有限公司生产)。1.2试验设计试验共设5个处理:2.5%五氟磺草胺油悬浮剂40ml/667m2、60ml/667m2、80ml/667m2,36%秧草净40g/667m2,以不用药为对照。1.3试验概况试验田设在武进区礼嘉镇新路村施文明的承包田中,前茬为小麦。水稻品种为银玉2084,于6月6日上午人工…     

丙草胺对干籽直播稻安全性的研究

水稻干籽播种,播后2~4 d施30%丙草胺EC 2 250 mL/hm2或30%丙草胺EC 2 250 mL/hm2+10%苄嘧磺隆WP 300 g/hm2,稻田进行湿润管理,对水稻出苗及生长安全。使用丙草胺后淹水,水稻出苗率下降,齐苗期、第一叶抽出期推迟,叶片、叶鞘缩短,稻苗矮小,其药害程度随淹水时间的延长、用药量的增加而加重。干籽直播稻田使用丙草胺必须严格把握两点:一是掌握在播种上水后2~4 d用药;二是三沟配套,排灌通畅,施药后至齐苗前田间无积水,确保幼根先于幼芽长出。     

丙草胺防除麦田硬草技术初探

硬草（Sclerochloakengiana）是苏北沿海稻麦轮作麦田的主要禾本科杂草,目前生产上应用的防除药剂中,均存在着不同程度的缺陷,或除草效果虽较好,但药后通多雨易造成麦苗药害;或在土壤湿度大时施药对麦苗安全,但又存在着干旱时施药除草效果差的不足。为了能安全高效地控制麦田硬草,亟需筛选出一种既除草效果稳定,又对麦苗安全的药剂。为此,笔者对瑞士诺华公司生产的丙草胺（Rifit）防除麦田硬草效果,及其对麦苗的安全性进行了一系列的试验研究,已获得初步结果,现报告如下。1材料与方法1．1播后苗前土壤封闭试验试验处理有：（1…     

噁草酮防除直播稻田杂草稻的施用技术

为确立噁草酮防除直播稻田杂草稻的施用技术,通过温室盆栽试验比较了噁草酮在不同土壤水分环境下对栽培稻的安全性及对杂草稻的防效,并在大田中比较了不同直播方式下其对杂草稻的防效及栽培稻产量的影响。结果表明,透气条件下,噁草酮对栽培稻的药害最低,但对杂草稻的防效也较差;饱和水分条件下对杂草稻防效较好,150 g(a.i.)/hm~2时其出苗率和鲜重的抑制率达89.61%和61.87%,超过450 g(a.i.)/hm~2时完全抑制出苗;但药后播种对栽培稻安全性较高,600 g(a.i.)/hm~2下对其出苗率和鲜重的抑制率仅分别为38.06%和39.96%,播后施药的药害较重,最低剂量150 g(a.i.)/hm~2时抑制率已分别达88.77%和45.52%;淹水条件下,虽对杂草稻有100%的防效,但也完全抑制栽培稻出苗。大田施用噁草酮300、450、600 g(a.i.)/hm~2,旱直播和水直播方式下杂草稻株防效分别为26.88%、43.54%、44.45%和84.88%、85.74%、90.92%;鲜重防效分别为11.58%、20.16%、27.33%和30.86%、53.68%、80.15%。旱直播和水直播方式下施用量分别超过450、300 g/hm~2时栽培稻产量显著增加。综合分析,推荐水直播整地后泥水状态施用300 g(a.i.)/hm~2噁草酮,水层落干后播种,保持土壤湿润且土表不出现水渍,栽培稻顺利出苗后及时上水且不淹没苗心为宜。     

苄嘧磺隆·丙草胺颗粒剂防除直播稻田杂草的效果

0.2%苄嘧磺隆·丙草胺颗粒剂在水稻直播田水稻1叶1心期施用,田间保持湿润,对水稻田的千金子、稗草、碎米莎草和马齿苋等都有较好的防效.使用其制剂10kg/667m2和12kg/667m2,药后45d,杂草株防效分别为90.15%和98.74%,鲜重防效分别为90.35%和98.20%,且对水稻安全,可增产稻谷22.75%和24.10%.     

丙草苄防除旱直播稻田杂草的应用技术

由于直播稻田干干湿湿 ,封行期推迟 ,对杂草的发生极有利 ,因而旱直播稻田杂草具有发生种类多、发生期长、数量大、危害严重等特点 ,若不及时进行化除 ,往往会形成草荒 ,对水稻高产丰收构成极大威胁。因此 ,寻求对旱直播稻田杂草防除效果好 ,对水稻秧苗安全可靠的除草剂是旱直播稻田杂草化除上亟需解决的难题。为了进一步明确丙草苄防除旱直播稻田杂草的化除效果、应用技术及对水稻的安全性 ,２０００年在通州市进行了丙草苄防除直播稻田杂草试验 ,取得了理想的结果。现将试验结果整理如下 :一、材料与方法１．供试药剂及水稻品种。１６%丙…     

噁唑酰草胺桶混灭草松防除直播稻田杂草试验初报

为明确10%噁唑酰草胺EC与阔叶草除草剂混用防除水稻田杂草效果,用噁唑酰草胺与灭草松桶混防除直播稻田杂草进行了试验。结果表明,杂草3～5叶期,使用10%噁唑酰草胺EC 1 200～1 800 mL/hm2,桶混48%灭草松SL 1 500～2 250 mL/hm2,对稗草、千金子、马唐、鳢肠、丁香蓼、异型莎草等多种杂草均有较好防效,且对水稻比较安全。     

丙草胺普草克防除麦田硬草初步研究

硬草是江苏农垦系统麦田的主要恶性杂草 ,而目前生产上所应用的除草剂 ,均存在着不同程度的缺陷。有的防除效果虽好 ,但药后遇多雨天气 ,易造成麦苗药害 ;有的在土壤干旱时 ,除草效果欠佳。为了安全高效地控制麦田硬草 ,垦区农场对丙草胺和普草克防除硬草进行了多次试验。1　丙草胺防除硬草1 .1　 1 997年试验结果1 997年秋播后多阴雨 ,1 1月中旬至 1 2月底累计降水达 1 6 4.8ｍｍ。新洋农场首先试用丙草胺在大麦田播后苗前进行土壤封闭化除。结果表明 ,亩用 5 0 %丙草胺ＥＣ6 0、80ｍｌ,冬前对麦田硬草的株防效达到 80 %以上 ,略差于乙草胺…     

苄嘧磺隆·丙草胺颗粒剂防除直播稻田杂草的效果

0．2％苄嘧磺隆·丙草胺颗粒剂在水稻直播田水稻1叶1心期施用,田间保持湿润,对水稻田的千金子、稗草、碎米莎草和马齿苋等都有较好的防效。使用其制剂10kg／667m^2和12kg／667m^2,药后45d,杂草株防效分别为90．15％和98．74％,鲜重防效分别为90．35％和98．20％。且对水稻安全,可增产稻谷22．75％和24．10％。     

吡嘧·丙草胺大粒剂防除移栽稻田一年生杂草的效果

为明确16.5%吡嘧·丙草胺大粒剂对移栽水稻田的一年生杂草稗草、千金子、矮慈姑和异型莎草的防效及对水稻的安全性,进行了田间药效试验。结果表明,水稻移栽7d后撒施16.5%吡嘧·丙草胺大粒剂200~300g/667m~2,可以有效防除上述杂草。药后45 d该药剂4个不同用量处理对总草的株防效和鲜质量防效分别为89.48%~98.12%和89.96%~98.65%,均显著高于两个单剂处理,而且对水稻生长安全,不影响水稻产量。     

Chemical control of weedy rice in precise hill‐direct‐seeded rice in South China

Precise hill‐direct‐seeded rice, which is both cost‐ and labor‐saving, is based on the direct seeding of rice by using a precision rice hill‐drop drilling machine. Weedy rice (Oryza sativa f. spontanea), also known as “red rice”, is a major weed in precise hill‐direct‐seeded rice, causing an ≤80% yield loss and a reduction in grain quality. The aim of this study was to evaluate the control efficiency of weedy rice by pretilachlor (a pre‐emergence herbicide) and fenclorim (a safener) and their safety for precise hill‐direct‐seeded rice in two consecutive years. The amount of rice seed germination was accelerated by soaking the seeds in the safener at 0.67 g ai L^?1 for 1 h before sowing. The pre‐emergence pretilachlor treatments were applied 2 days after sowing cultured rice. The inhibition of the shoot fresh weight of the cultured rice was reduced by 3.3, 6.4 and 7.4% with 450, 900 and 1350 g ai ha^?1 of pretilachlor at 32 days after sowing (DAS) and that of the root fresh weight was reduced by 2.6, 4.9 and 8.1%, respectively. With fenclorim and pretilachlor in a precise hill‐direct‐seeded rice field in 2010 and 2011, the weedy rice control efficiency at 32 DAS was reduced by 100 and 98.0%, respectively. The pre‐emergence pretilachlor treatments that were applied at 2 DAS were much more efficient in the weedy rice control and less inhibitory to the cultured rice growth. The rice yield was increased by 26.1–26.7% in the mechanical precise hill‐direct‐seeded rice, relative to the manual‐seeding rice, with the application of fenclorim and pretilachlor.     

Relationship between safening activity of dymron and fenclorim to pretilachlor and glutathione S-transferase activity in rice

Dymron [1‐(α,α‐dimethybenzyl)‐3‐(p‐tolyl)urea] and fenclorim (4,6‐dichloro‐2‐phenylpyrimidine) were found to exhibit a safening activity on the growth of rice (Oryza sativa L.) seedlings against pretilachlor [2‐chloro‐2′,6′diethyl‐N‐(2‐propoxyethyl)acetanilide] injury. By pretilachlor treatment at 10^–6 and 10^–5 mol L^–1, the elongation of the third leaves of rice seedlings was reduced by approximately 20 and 40%, and that of the fourth leaves was reduced by approximately 40 and 80%, respectively. Upon the treatment of dymron at 3 × 10^–6 and 10^–5 mol L^–1 in combination with pretilachlor, the growth inhibition was half alleviated in the third leaves, and the length of the fourth leaves was almost recovered from 10^–6 mol L^‐1 pretilachlor injury, and was 20–25% recovered from 10^–5 mol L^–1 pretilachlor injury. Upon the treatment of fenclorim at 3 × 10^–6 and 10^–5 mol L^–1 in combination with pretilachlor, the growth inhibition of rice seedlings was almost alleviated in both the third and the fourth leaves. This result indicated that dymron and fenclorim showed almost the same safening effect on the fourth leaf growth against 10^–6 mol L^‐1 pretilachlor injury, although fenclorim showed higher effects at higher concentrations of pretilachlor. Glutathione S‐transferase (GST) activities in rice seedlings were investigated after being treated with a herbicide and safener. By pretilachlor treatment at 10^–6 and 10^–5 mol L^–1, the GST activity was approximately 32 and 72% increased in roots, respectively, and a little increased (7–13%) in shoots of two‐leaf‐stage rice seedlings. By dymron treatment at 3 × 10^–6?10^–5 mol L^–1, the GST activity was 2–30% increased in roots, but was not increased in shoots. By their combination treatment, the GST activity was almost the same or less than that by treatment with pretilachlor alone. In contrast, by fenclorim treatment alone, the GST activity was 43–52 and 33–45% increased in roots and shoots of rice seedlings, respectively. By the combination treatment of pretilachlor and fenclorim, the GST activity was increased 73–126% in shoots and 101–139% in roots, and was much more increased in both shoots and roots compared with treatment of pretilachlor or fenclorim alone. It was found that dymron showed less effect in increasing the GST activity than fenclorim. It is also suggested that dymron did not increase the GST activity in shoots but did increase it slightly in roots, and showed almost no effect on GST increase by pretilachlor in shoots, or rather reduced the increase in roots. From the above results, fenclorim and dymron may have different mechanisms of safening effects on the protection of rice seedlings against pretilachlor injury.     

杂草稻与栽培稻叶片生长的竞争性研究

杂草稻造成栽培稻产量的损失主要表现为叶片间的相互竞争。争夺空间、争夺光照矛盾突出。杂草稻主茎叶片多于栽培稻,最大叶片长于栽培稻,最大叶片宽于栽培稻,叶片披散,形似杂交稻叶。如果在667 m2旱直播稻田接种2.5 kg粳性杂草稻籽,栽培稻上部全被杂草稻稻叶覆盖,栽培稻植株瘦黄、弱小,茎、蘖逐步退化消亡,造成基本绝产。     

Differential safening activity of dymron and fenclorim on pretilachlor injury in rice seedlings in soil

The safening activity of dymron [1-(α,α-dimethylbenzyl)-3-( p -tolyl)urea] and fenclorim [4,6-dichloro-2-phenylpyrimidine] on the phytotoxic activity of pretilachlor [2-chloro-2',6'-diethyl- N- (2-propoxyethyl)acetanilide] on rice seedlings was examined in both water and soil culture. The safening activity of fenclorim in water culture was greater than that of dymron, whereas the activity of fenclorim in soil was lower than that of dymron. The fenclorim concentration in soil water was lower than that of dymron at all times when determined after the application at the same concentrations. The phytotoxic activity of pretilachlor and the safening activities of dymron and fenclorim were well correlated with the concentration of each in soil water but not with the amount in total soil. The adsorption of fenclorim on soil solids was greater than those of dymron and pretilachlor. It was suggested that both the phytotoxic activity of pretilachlor and the safening activities of dymron and fenclorim were dependent on their concentrations in soil water, which were primarily dominated by the adsorption on soil.     

Effect of pretilachlor and fenclorim on carbohydrate and protein formation in relation to their persistence in rice

The persistence of pretilachlor applied to rice singly or in combination with the safener fenclorim was investigated in connection with starch, glucose and protein formation. The addition of fenclorim to pretilachlor did not reduce the accumulation of the latter, but reduced its persistence in rice shoots, while the presence of pretilachlor did not affect the persistence of fenclorim, but significantly increased its accumulation in the shoots. Therefore the safening effect of fenclorim consisted of a more rapid detoxification of pretilachlor. Over the period of pretilachlor and fenclorim detoxification, decreases in starch content, partially counterbalanced by increases of free glucose, and decreases in total protein content were observed in pretilachlor-treated shoots; decreases in both starch and free glucose, as well as in total protein content, were observed in fenclorim -treated shoots compared with the untreated controls. The decreases in starch and total glucose appeared to be a direct consequence of reduced glucokinase and ribulose-1,5-bisphosphate carboxylase activity, and the decrease in total protein an indirect consequence of reduced glutamine synthetase and glutamate synthase activity, in response to pretilachlor and fenclorim treatments.     

Differential glutathione S-transferase isozyme activities in rice and early watergrass seedlings

Glutathione S -transferase (GST) isozymes were investigated in one-leaf-stage rice ( Oryza sativa L. cv. Nipponbare) and early watergrass ( Echinochloa oryzicola Vasing) shoots after being induced by treatment with a combination of pretilachlor [2-chloro-2',6'-diethyl-N-(2-propoxyethyl)acetanilide] and fenclorim (4,6-dichloro-2-phenylpyrimidine) using DEAE-Sephacel anion exchange chromatography. Non-treated plants contained GST isozymes that had activity to the following substrates: three isozymes for l-chloro-2,4-dinitrobenzene (CDNB), six isozymes for pretilachlor and three isozymes for fenclorim in rice shoots; and four isozymes for CDNB, three or four isozymes for pretilachlor and two or three isozymes for fenclorim in early watergrass shoots. Glutathione S -transferase isozyme activities of non-treated plants were higher in rice than in early watergrass, especially in the case of GST activity with fenclorim as a substrate. Pretreatment of rice roots with a combination of pretilachlor and fenclorim increased the activity of the constitutively expressed isozymes that exhibited activity with CDNB, pretilachlor and fenclorim. This pretreatment also caused the appearance of one new GST(fenclorim) isozyme. Pretreatment of early watergrass roots with a combination of pretilachlor and fenclorim produced almost no increase in activity of some constitutively expressed isozymes that exhibited activity to CDNB and fenclorim, although it partly increased the peaks to corresponding to pretilachlor. The induction of GST was higher in rice than that in early watergrass. These results indicated that the isozyme pattern and substrate specificity of GST isozymes in rice were different from those in early watergrass. Furthermore, the selectivity of pretilachlor between rice and early watergrass may be related to different constitutively expressed GST(pretilachlor) isozyme activities and the induction of GST(pretilachlor) isozyme activities in the combination treatment.     

杂草稻研究现状及利用展望

杂草稻作为一种稻田伴生杂草,严重影响了水稻的产量和稻米品质。尤其是近年来随着直播稻的推广和机械化程度的提高,杂草稻的危害有加重的趋势。同时,杂草稻的抗逆性非常强,与水稻的亲缘关系也非常近,是一个极有利用价值的天然基因库,是水稻育种的宝贵资源。本文就杂草稻的生物学特性、分布、起源、分类、防除等方面的研究做了概述,并对其利用前景进行展望,提出了有待进一步深入研究的问题。     

Toxicity and selective mechanism of imazamox by weedy rice and imidazolinone-resistant rice in China

Weedy rice (Oryza spp.) is a notorious weed in direct-seeding paddy fields. Because it has anatomical and physiological traits similar to those of cultivated rice, no selective herbicide is effective in controlling weedy rice growing among conventional rice cultivars. Imidazolinone (IMI)-resistant rice lines JD372 and JJ818 have been planted with imazamox to control weedy rice in Jiangsu and Shanghai, China. Whole-plant dose–response analysis showed that imazamox exhibited high efficacy against three populations of weedy rice. The ED₉₀ of weedy rice populations FN-5, GY-8, and HY-3 were 46.87, 61.43, and 52.17 g a.i. ha⁻¹, respectively, close to the recommended field dose (50 g a.i. ha⁻¹) of imazamox. Conversely, the ED₁₀ values of JD372 and JJ818 were slightly lower than 50 g a.i. ha⁻¹. These findings indicate that imazamox can control weedy rice production in JD372 and JJ818 fields. The acetolactate synthase (ALS) sensitivity of JD372 in vitro was 1714.89-fold lower to imazamox than was that of FN-5. ALS gene sequencing revealed a Ser653Asn point mutation—a common mutation that confers resistance to IMI herbicides in JD372. In addition, higher ALS expression levels in JD372 were found at 24 and 72 h after imazamox treatment. ALS overexpression might partially compensate for the ALS activity of JD372 that was suppressed by imazamox.